mujoco

<mujoco model="Tendon">
  <option solver="PGS"/>

  <default>
    <site size=".02" rgba="0 .8 0 1"/>
    <geom condim="1"/>
  </default>

  <worldbody>
    <light pos="1 0 4" dir="-1 0 -4"/>
    <light pos="-1 0 4" dir="1 0 -4"/>
    <geom type="plane" size="2 2 .01"/>
    <site name="ceiling" pos="0.01 0.02 2.4"/>

    <body pos="0 0 1.5">
      <freejoint/>
      <site name="hook" pos="0 0 .3"/>
      <site name="bulb"/>
      <geom name="bulb" size=".3" rgba="0 0 .8 1" density="100" contype="0" conaffinity="0"/>
    </body>

    <replicate count="18" euler="0 0 20">
      <body pos=".2 0 1.5">
        <freejoint/>
        <site name="a"/>
        <geom rgba=".8 0 .4 1" size=".03"/>
      </body>
      <body pos="1.2 0 1.5">
        <freejoint/>
        <site name="b"/>
        <geom rgba=".8 .4 0 1" size=".1"/>
      </body>
    </replicate>
  </worldbody>

  <tendon>
    <spatial springlength="0 0.5" stiffness="10000">
      <site site="ceiling"/>
      <site site="hook"/>
    </spatial>
    <spatial range="0 0.5">
      <site site="a"/>
      <geom geom="bulb" sidesite="bulb"/>
      <site site="b"/>
    </spatial>
  </tendon>
</mujoco>